Acta Biológica Colombiana ISSN: 0120-548X ISSN: 1900-1649 Universidad Nacional de Colombia, Facultad de Ciencias, Departamento de Biología EXPERIMENTAL APPROACHES FOR THE EVALUATION OF ALLELOPATHIC INTERACTIONS BETWEEN HERMATYPIC CORALS AND MARINE BENTHIC CYANOBACTERIA IN THE COLOMBIAN CARIBBEAN PUYANA, Mónica; PRATO, Julián Alberto; NIETO, Christian Felipe; RAMOS, Freddy Alejandro; CASTELLANOS, Leonardo; PINZÓN, Paola; ZÁRATE, Juan Camilo EXPERIMENTAL APPROACHES FOR THE EVALUATION OF ALLELOPATHIC INTERACTIONS BETWEEN HERMATYPIC CORALS AND MARINE BENTHIC CYANOBACTERIA IN THE COLOMBIAN CARIBBEAN Acta Biológica Colombiana, vol. 24, no. 2, 2019 Universidad Nacional de Colombia, Facultad de Ciencias, Departamento de Biología Available in: http://www.redalyc.org/articulo.oa?id=319060771005 DOI: 10.15446/abc.v24n2.72706 PDF generated from XML JATS4R by Redalyc Project academic non-profit, developed under the open access initiative Artículos EXPERIMENTAL APPROACHES FOR THE EVALUATION OF ALLELOPATHIC INTERACTIONS BETWEEN HERMATYPIC CORALS AND MARINE BENTHIC CYANOBACTERIA IN THE COLOMBIAN CARIBBEAN Aproximaciones experimentales para la evaluación de interacciones alelopáticas entre corales hermatípicos y cianobacterias marinas bentónicas en el Caribe Colombiano Mónica PUYANA 1* Universidad de Bogotá Jorge Tadeo Lozano, Colombia 2 Acta Biológica Colombiana, vol. 24, no. Julián Alberto PRATO 2, 2019 Universidad Nacional de Colombia, Colombia Universidad Nacional de Colombia, Christian Felipe NIETO 3 Facultad de Ciencias, Departamento de Biología Universidad Nacional Autónoma de México, Mexico 4 Received: 06 June 2018 Freddy Alejandro RAMOS Revised document received: 10 September 2018 Universidad Nacional de Colombia, Colombia Accepted: 27 November 2018 Leonardo CASTELLANOS 4 DOI: 10.15446/abc.v24n2.72706 Universidad Nacional de Colombia, Colombia Paola PINZÓN 1 CC BY-NC-SA Universidad de Bogotá Jorge Tadeo Lozano, Colombia Juan Camilo ZÁRATE 5 Investigador científico- CEINER LTDA ABSTRACT: Blooms of marine benthic cyanobacteria are recurrent in several locations at the Colombian Caribbean. In these events, cyanobacteria grow over the substrate and benthic organisms although their effect has not been fully assessed. is study evaluated interactions between cyanobacteria and hermatypic corals, in order to identify any deleterious effects that could be related to allelopathic mechanisms. Organic extracts from cyanobacteria collected in San Andres, Old Providence and Rosario islands were tested against embryos of the reef-building coral Orbicella annularis. e indirect effect of cyanobacterial extracts was also assessed by resuspending the extracts in seawater and monitoring polyp retraction and recovery of the coral Madracis mirabilis (=auretenra). Additionally, the effect of direct contact between cyanobacterial extracts and the coral Porites porites was assessed by incorporating cyanobacterial extracts into Phytagel™ gels and placed in direct contact with the coral. Aer 24, 48 and 72 h of exposure, chromatographic profiles of associated zooxanthellae was evaluated by HPLC. A deleterious effect on the zooxanthellae was evidenced by an increase in pheophytin, a degradation product from chlorophyll. e competitive abilities of algae and cyanobacteria should be considered as a constraint to reef restoration initiatives. PDF generated from XML JATS4R by Redalyc Project academic non-profit, developed under the open access initiative Mónica PUYANA, et al. EXPERIMENTAL APPROACHES FOR THE EVALUATION OF ALLELOPATHIC INTERACTIONS BETWEEN HERMATYPIC CORALS AND MARINE BENTHIC C... Cyanobacteria have the ability to compete with corals due to their growth rates, defenses against herbivory and potentially allelopathic mechanisms. Keywords: Alellopathy, corals, cyanobacteria, interspecific competition. RESUMEN: Afloramientos de cianobacterias marinas bentónicas son recurrentes en varias localidades del Caribe colombiano. En estos eventos, las cianobacterias crecen sobre el sustrato y organismos bentónicos sin que su efecto se haya evaluado completamente. Este estudio evaluó interacciones entre cianobacterias y corales hermatípicos con el fin de identificar efectos perjudiciales que podrían estar relacionados con mecanismos alelopáticos. Extractos orgánicos de cianobacterias recolectadas en las islas de San Andrés, Providencia y las Islas del Rosario fueron evaluados contra embriones del coral hermatípico Orbicella annularis. También se evaluó el efecto indirecto de extractos de cianobacterias resuspendidos en agua de mar para determinar retracción de pólipos y recuperación del coral Madracis mirabilis (=auretenra). Adicionalmente, se evaluó el efecto del contacto directo de extractos de cianobacterias y el coral Porites porites mediante la incorporación de los extractos en geles de PhytagelTM dispuestos en contacto directo con el coral. Después de 24, 48 y 72 h de exposición, los perfiles cromatográficos de las zooxantelas asociadas al coral fueron evaluados por HPLC. Un efecto negativo sobre las zooxantelas se evidenció por el incremento en feofitina, producto de degradación de la clorofila. Las capacidades competitivas de algas y cianobacterias debieran considerarse como un factor que podría incidir negativamente en iniciativas de restauración arrecifal. Las cianobacterias tienen la capacidad de competir con corales debido a sus tasas de crecimiento, defensas contra herbivoría y potenciales mecanismos alelopáticos. Palabras clave: Alelopatía, cianobacterias, competencia interespecífica, corales. INTRODUCTION Coral reefs are one of the most important, diverse and productive ecosystems on the planet. ey thrive in clear waters of tropical seas and are fundamental in the development of a very complex ecosystem. Coral reefs provide substantial economic and ecological services to society and the environment. e reef structure protects coastal areas, mangroves and seagrasses from erosion (Moberg and Folke, 1999; Ritson-Williams et al., 2009). e reef structure also provides habitat for many organisms including species of commercial interest such as crabs, lobsters and mollusks (Jennings and Polunin, 1996; Birkeland, 1997; Mumby and Steneck, 2008). Competition determines the structure and composition of coral reefs communities (Birkeland, 1997). In coral reefs, the increasing competition between algae and corals has become an important factor for reef resilience (reviewed in Puyana, 2018). e process of coral reef recovery is difficult because juvenile corals must settle in substrates now dominated by algae and cyanobacteria which are very effective colonizers aer disturbances (McCook et al., 2001; Hughes et al., 2007; Diaz- Pulido et al., 2010). e dominance of algae and cyanobacteria can become a serious bottleneck for the settlement and recruitment of corals, depending on the local and dominant characteristics of algal communities (McCook et al., 2001; Diaz-Pulido et al., 2010). Benthic mats of algae and/or cyanobacteria occupy available substrate but also form physical barriers hampering coral recruitment (McCook et al., 2001; Diaz-Pulido et al., 2010; Ford et al., 2018). Experimental PDF generated from XML JATS4R by Redalyc Project academic non-profit, developed under the open access initiative Acta Biológica Colombiana, 2019, 24(2), ISSN: 0120-548X / 1900-1649 evidence has shown that cyanobacterial mats rely on chemically mediated effects affecting the settlement, survival, and recruitment of coral larvae (Kuffner et al., 2004; Kuffner et al., 2006). Hence allelopathic mechanisms may play significant roles in the processes of competition between coral reef benthic organisms, impacting reproductive processes, physiology, growth, and survival of reef communities (acker et al., 1998; Chaves Fonnegra et al., 2008; Chadwick and Morrow, 2011). Allelopathy is the process by which an organism produces chemical compounds that negatively affect the growth, development, health, behavior, and reproduction or population biology of another species. Allelopathy has been very difficult to demonstrate in aquatic environments due to the hydrodynamic character and the complexity of communities in those environments. is mechanism may be frequent in sessile organisms that compete for resources such as space or access to light including algae and sponges, among others (De Nys et al., 1991; Littler and Littler, 1997; Steinberg et al., 1998; Engel and Pawlik, 2000; Richelle-Maurer et al., 2003; Titlyanov et al., 2007; Chaves-Fonnegra et al., 2008). Marine cyanobacteria produce a large number of biologically active compounds, important for their survival (Nagle and Paul, 1998; Tan and Goh, 2009; Engene et al., 2011; Leão et al., 2012), for the establishment and persistence of cyanobacterial blooms (Leão et al., 2012) and as inhibitors of potential competitors such as algae, microalgae, aquatic plants and even other species of cyanobacteria (Jüttner et al., 2001; Berry et al., 2008). Currently, cyanobacteria are a frequent sight in several reef locations, although reef ecologists still consider algae and cyanobacteria as the same category when performing field surveys. Cyanobacterial mats form multispecies consortia and grow on other organisms such as corals and octocorals causing polyp retraction, bleaching or the death of coral tissue under cyanobacterial mats or in areas where mats come in direct contact with corals (Paul et al., 2005; Smith et al., 2008; Puyana and Prato, 2013; Puyana et al., 2015; Ford et al., 2018) (Figure 1). PDF generated from XML JATS4R by Redalyc Project academic non-profit, developed